My thinking for true 27.5+ compatibility is 45mm internal+ rim and a 3.0" wide tire. I can fit that smaller combo of i35 and a WTB 2.8 Trailblazer or Ranger on three different 650b hardtails in my garage.

I just watched over the shoulder of my co worker as he clicked to order a black ano Toir with green links and DVO topaz to pair with his green DVO diamond. it was glorious to see happen, and all for near 1/2 off. New bike day is awesome